GAMMARTH, Tunisia (AP) — The head of the World Health Organization says the agency will be upfront about its handling of the Ebola outbreak, following an internal report that details failures in containing the virus.

In the draft document obtained by the Associated Press, the WHO says "nearly everyone" involved in the Ebola response failed to notice factors that turned the outbreak into the biggest on record. It blames incompetent staff, bureaucracy and a lack of reliable information.

WHO Director Margaret Chan said Monday that the report was a "work in progress." Speaking on the sidelines of a conference in Tunisia, she said "I have promised WHO will be fully transparent and accountable."

Nearly half of the more than 9,000 people who have contracted Ebola in West Africa this year have died.